I want to have the last name and first name on the same line in the Ulkit 3 slider (see attachment). So I have to reduce the size a bit so that it lines up. Also for the function. Where do I do that?

This can be set with the correct css code. Insert the following code in the template options for user-defined css code (custom code) and adjust the font size as you like. Currently 1rem but as I said, just adjust it.